best antenna

[iamnothere]

A nightmare , to bypass the China GFW , I connect internet with full time VPN service . the trace route show package to FR24 server .
Screen Shot 2015-07-24 at 10.40.10 PM.jpg

It's okay , because it can be much worth .
without VPN , package to FR24 server .
Screen Shot 2015-07-24 at 10.41.27 PM.jpg

lost package 45% is normal , it can be up to 95% sometime .

[abcd567]

@abcd567

Yes , just like the pic show . I still able picked up signal from the direction , it depends on the plant alt , Shanghai downtown is just like a concrete city , I stay here only because $ and save traffic time , I'd move far far away when I retired .

The jumping mostly happened while I use RTL1090 on Windows system , after I switch to dump1090 its getting much better I think , and the --ppm correction do help a lot .

Like my situation. I am not exactly in middle of downtown, in comparatively less "concrete city" but still many tall buildings around. I myself live in a tall building, but not on a very high floor. Most of surrounding buildings are much higher than my antenna located inside my apartment.

[abcd567]

A nightmare , to bypass the China GFW , I connect internet with full time VPN service . the trace route show package to FR24 server .
[ATTACH=CONFIG]6274[/ATTACH]

It's okay , because it can be much worth .
without VPN , package to FR24 server .
[ATTACH=CONFIG]6275[/ATTACH]

lost package 45% is normal , it can be up to 95% sometime .

Oops! This is too bad, a nightmare! I am lucky we dont have this situation in Toronto.

[iamnothere]

Before I move to China , I never heard about VPN .

Even the broadband is 50MB downlink 5MB uplink , you don't own personal IP , so I purchase VPN personal IP service for Plant Plotter , to become a MLAT ground station and master user , bad bad bad news , I just found out I am the only Plant Plotter MLAT station in China .

[abcd567]

The Spaghetti Pilot

[Rooster]

Thats drugs for you ! hahahaaa

[abcd567]

SIMULATION OF 2 DIY ANTENNAS

Simulation 1 of 2: SPIDER (8 Legged )
Gain = 1.7 dBi
SWR (75 ohms) = 1.3






Simulation 2 of 2: CANTENNA
Gain = 1.9 dBi
SWR (75 ohms) = 1.5

[Birdie]

Before I move to China , I never heard about VPN .

Even the broadband is 50MB downlink 5MB uplink , you don't own personal IP , so I purchase VPN personal IP service for Plant Plotter , to become a MLAT ground station and master user , bad bad bad news , I just found out I am the only Plant Plotter MLAT station in China .

What kind of plant you plotting in China ?

Potatoes, Corn, Vegetables, Cabbages, Leek, Apple, Oranges ?

[1090 MHz]

Yes this is ground traffic and it is a transponder, but with a limited amount of power compared to an aircraft. This is what they are using to track ground vehicles, it's called a VeeLo made by Saab. The VeeLo's transmit only 20 watts so you have to be close to the airport to pick one up. I had a chance to test the range of a VeeLo with a representative from Nav Canada and it had a 5 Km range from my tower.

http://saab.com/globalassets/commerc...s_brochure.pdf

Look what I caught on my receiver:
A Crazy Pilot Taxiing Under Influence of Alcohol?
No it is an airport maintenance vehicle fitted with ADS-B transponder!

[1090 MHz]

Here is the actual VeeLo test we did... max range was 5 Km and GPS data was highly accurate and could even tell me the lane the vehicle was driving (flying) in on the 407.

It's kind of funny to see a jet driving down the 407 !

[abcd567]

The largest plane Stratolaunch, nicknamed “Roc” features two fuselages, six Pratt & Whitney jet engines, 28 landing gear wheels, and a whopping 385 foot wingspan.

If you were to put the center of this airplane on a football field, its wingtips would extend beyond the goalposts by about 15 feet on each side.

Those dimensions make it 65 feet wider than the legendary “Spruce Goose” H-4 Hercules, 95 feet wider than the spaceship-carrying Soviet Antonov An-225, and 123 feet wider than the modern Airbus A380. In fact, it is being constructed using pieces of two already quite large planes–a pair of disused Boeing 747s.

[abcd567]

Here is the actual VeeLo test we did... max range was 5 Km and GPS data was highly accurate and could even tell me the lane the vehicle was driving (flying) in on the 407.

It's kind of funny to see a jet driving down the 407 !

yes, it is funny & shocking when seen for the first time.

[abcd567]

With recent improvement in my antenna gain, I have started picking up planes on ground at Toronto CYYZ airport. The strange thing is that the Toronto airport is TOTALLY behind a large high rise building when viewed from my antenna location, my antenna is lower than the surrounding buildings, inside my apartment, and I dont see any way the microwaves can penetrate and cross the large high rise building with left-over signal strength above the threshold of the receiver. I think the only possibility is multiple reflections from glazed glasses of buildings nearby, as shown in attache sketch.

[1090 MHz]

.........The strange thing is that the Toronto airport is TOTALLY behind a large high rise building when viewed from my antenna location, my antenna is lower than the surrounding buildings, inside my apartment, and I don't see any way the microwaves can penetrate and cross the large high rise building ........I think the only possibility is multiple reflections from glazed glasses of buildings nearby, as shown in attache sketch.

Yes that signal will bounce off of solid objects ... this is why frequency band 1 to 2 GHz is preferred for the operation of long-range air-surveillance radars

[SpaxmoidJAm]

Just confirms CoCo is not trivial to tune, at least for UHF and above.
Small variation on cable VF and construction technique can result in unpredictable results which are imposible to correct without a VNA.

I am still experimenting with my CoCo to see if I can make it robust to construction variability but this is not easy.

I am also going to test some variation of collinear which does not require coaxial cable and could be easy to build.

[ATTACH=CONFIG]5799[/ATTACH]

Need to test. 2 stacked half wave like on the picture should be OK but feed impedance might be very low when stacking more half wave phase/radiating sections above.
If there are antenna specialists on the forum, would like to hear what they think.
The top sections could be assembled on a fiber glass rod (8mm rods used for kites) which would allow to make the assembly precise and easy.
The phasing line is just very small diameter copper wire.

Will try to get something done for next weekend.
JL

well i fainally got around to testing the one i built of this (short story i forgot to order connectors also forgetting i built it)

the location i tested isnt the best suited nor was the coax i was using quite long enough but these things only make a minor difference to the antenna.
4.jpg

by moving me and the aerial i was only able to move things around by best a db and a few MHz.